Damage Constitutive Of Recycled Concrete And The Safety Research Of Multi-ribbed Composite Wall In Different Replacement

The material of the multi-ribbed composite wall, filled in the gridiron, could consume industrial and agricultural waste with large amount. Meanwhile, the multi-ribbed composite wall structure is a kind of new structural system, which has the light weight, good seismic performance and energy-saving effect. So, the composite wall is a new better structure, which has the good application perspective in the future, and the theoretical and application achievements have been obtained by continuous efforts of research group. However, this point of the multi-ribbed wall, which the new materials use in the new structure, has still lacked. Recycled concrete is the green building materials, which can decrease the exploitation of natural sandrock, can reuse the discarded building waste and fulfils the internal cycle of building materials (building materials-waste-building materials). Now, the common concrete in the frame grid and the side frame of the multi-ribbed composite wall is replaced with the recycled concrete. By mean of those, not only the waste concrete could be reused and expand the application range of recycled concrete, but also the content of green is increased in the multi-ribbed composite wall and alleviate environmental pollution, moreover those coincide with the national requirement of sustainable development.Based on the former research, this paper emphasizes on the mechanical properties, three-dimensional constitutive model, evolution law of damage variables about the recycled concrete and the seismic performance of the recycled concrete multi-ribbed composite wall, the reliability of the structure based on the strength randomness of recycled concrete. The main research contents and achievements are summarized as follows: 1,The mathematic model of the strength and influence factors is built by step regression analysis; The optimum proportions of the recycled concrete strength are achieved by the objective function of strength and the constraint condition of the factors.The strength of recycled concrete (RC), which is influenced by various factors, is researched by the uniform test design. Quadratic function mathematical model for the compressive and splitting tensile strength is achieved by step regression analysis based on the results of experiment. The results show that the quadric mathematical model can describe accurately the inner relationship among the various factors and the RC strength; the mix proportions of RC based on the strengths (compressive resistance and splitting tensile resistance) are optimized, which can instruct the practical engineering.2,For the first time the triaxial compression test of recycled concrete is conducted, and the triaxial constitutive model is built. Moreover, the evolution law of damage variables of recycled concrete is researched.The triaxial compressive test of recycled concrete (RC) is made and the deformation features of recycled concrete are researched under the triaxial compressive. Based on the test and the theory of continuum damage mechanics, the triaxial compressive onstitutive model is suggested about the recycled concrete; the triaxial secant modulus of recycled concrete is deduced and the suitable damage variable is put forward, and acquires the evolution law of damage variable under different confining pressures.3,For the first time the seismic performances test of recycled concrete multi-ribbed composite wall is executed, and the stress mechanism of the wall is researched.Under low-cyclic horizontal loading, two recycled concrete multi-ribbed composite walls (composed of 100%,50%, recycled aggregate) are studied in this paper. The seismic behaviors of recycled concrete multi-ribbed composite wall, such as the failure patterns, hysteretic loop, ductility, deterioration of stiffness and energy dissipation, etc., are researched. Meanwhile, the stress distribution of wall is studied. All those provide the corresponding basis for the use of recycled concrete multi-ribbed composite wall in practice.4,The nonlinear finite element numerical model of the recycled concrete multi-ribbed composite wall is done. By the numerical model, the oblique section formula of recycled concrete wall is established by the first time, with considering the different ratio of the recycled aggregate replacement.Based on the former experiment, the deformation, bearing capacity of the recycled concrete multi-ribbed composite wall is analyzed by Ansys. And by the numerical model that has been proved, the oblique section formula of multi-ribbed composite wall is established, which provides the theoretical foundation.5,Based on the randomness of recycled concrete and the finite element probabilistic design, the reliability evaluation and the sensitivity analysis of the recycled concrete multi-ribbed composite wall are advanced under considering the different ratio of recycled aggregateBased on the predecessor research and by means of mathematical statistics, the probability distribution and statistical parameters of the recycled concrete with various strength and recycled aggregate replacement ratio are given. Based on the finite element probability design, probability distribution and statistical parameters of the recycled concrete, the reliability and the sensitivity of the recycled concrete multi-ribbed composite wall, considering the various factors, is system studied.